The present invention relates to plasticized sulfur prepared by specified heating and cooling. The plasticized sulfur is a good adhesive and can be used as a bonding agent in making pipe out of layers of paper.
Plasticized sulfur has been disclosed in various references, for example by J. I. Jin in "Chemistry of Plasticized Sulfur", Petroleum Division, A.C.S. Symposium, Vol. 19, No. 2, March 1974, pp. 234-241, and by C. Kinney Hancock in "Plasticized Sulfur Compositions for Traffic Marking", Industrial and Engineering Chemistry, Vol. 46, No. 11, November 1954, pp. 2431-2435. Exemplary patents disclosing plasticized sulfur (and heating temperatures at which the plasticized sulfur is formed) include U.S. Pat. No. 2,169,814, "Bonding and Coating Product" (heating temperatures of 150.degree.-160.degree. C.); U.S. Pat. No. 3,306,000, "Construction Method" (heating temperatures of 135-1751C); U.S. Pat. No. 3,316,115, "Marking Composition" (heating temperature of 160.degree. C.); U.S. Pat. No. 3,371,072, "Sulphur Resins" (heating temperatures of 100.degree.-200.degree. C., preferably 110.degree.-160.degree. C., U.S. Pat. No. 3,384,609, "Plasticized Sulphur" (heating temperatures of 120.degree.-250.degree. C., preferably 140.degree.-160.degree. C.); U.S. Pat. No. 3,434,852, "Plasticized Sulfur Compositions" (heating temperatures of 50.degree.-250.degree. C., preferably 100.degree.-200.degree. C., and exemplary temperatures of 130.degree.-170.degree. C.); U.S. Pat. No. 3,447,941, "Sprayable Sulfur Road Marking Compositions" (heating temperature of 150.degree. C.); U.S. Pat. No. 3,453,125, "Plasticized Sulfur Compositions" (heating temperatures of -20.degree.-250.degree. C. and exemplary temperatures of 138.degree.-170.degree. C.); U.S. Pat. No. 3,459,717, "Sulfur-Based Plastic Composition" (heating temperatures of 115.degree.-200.degree. C., preferably 140.degree.-170.degree. C.); U.S. Pat. No. 3,465,064, "Adhesive Plasticised Sulphur Containing an Olefine Polymer" (heating temperatures of 100.degree.-200.degree. C., preferably 140.degree.-150.degree. C.); U.S. Pat. 3,560,451, "Plastic and Nonflammable Sulfur Composition" (heating temperatures of 120.degree.-180.degree. C., preferably 140.degree.-160.degree. C.); U.S. Pat. No. 3,640,965, "Thermoplastic SulfurContaining Polymers"; U.S. Pat. No. 3,674,525, "Plasticized Sulfur Compositions" (heating temperatures of 50.degree.-250.degree. C. and exemplary temperature of about 155.degree. C.); U.S. Pat. No. 3,676,166, "Plasticized Sulfur Compositions" (heating temperatures of 75.degree.-400.degree. F., preferably 250.degree.-350.degree. F., and exemplary temperature of 300.degree. F.); U.S. Pat. No. 3,734,753, "Plasticized Sulfur Compositions" (heating temperatures of 118.degree.-250.degree. C., preferably 150.degree. C.); and U.S. Pat. No. 3,787,276, "Corrugated Cardboard Containing Sulphur Foam" (heating temperature of 110.degree. C.); also Ser. No. 286,627, now U.S. Pat. No. 3,823,019, "Mine Wall Coating" (heating temperatures of 240.degree.-320.degree. F., preferably 275.degree.-320.degree. F.), which application has been offered for license by the U.S. Bureau of Mines, discloses plasticized sulfur compositions.
As can be seen from the examples in the above patents, temperatures which are suggested by the patents for heating or carrying out a reaction to obtain the plasticized sulfur compositions are generally about 150.degree. C. (302.degree. F.). U.S. Pat. No. 3,734,753 thus discloses at Col. 2, line 50, with respect to preparation of plasticized sulfur compositions: "It is preferable to maintain the temperature of the reaction mixture at about 150.degree. C. since pure sulfur becomes viscous at 160.degree. C. and higher temperatures raise the cost of processing."
"Elemental Sulfur," edited by B. Meyer, Interscience Publ. (1965) discloses in Chapter 5 the sharp increase in sulfur viscosity at about 159.degree. C. Chapter 8 of "Elemental Sulfur" discloses as follows:
"Both the arsenic-modified and phosphorus-modified systems are dark red in color, have objectionable odors, and tend to recrystallize when exposed to light and air. Arsenic-sulfur systems are more stable and such materials have been fabricated into a variety of products including lenses, prisms, tubes, and fibers.
"Polymeric sulfides and polysulfides are more promising modifiers for elemental sulfur, tending to stabilize the material in a plasticized form. These materials, on heating with sulfur to temperatures above its polymerization point (159.degree. C.), form viscous liquids which on cooling show distinct polymeric properties. These compositions recrystallize elemental sulfur only after comparatively long periods of time, depending upon the concentration of polysulfide polymers used . . . Compositions having as little as 10-15% of the polymer [ethylene tetrasulfide], after heating to 160.degree.-175.degree. C., remain in a polymeric form several days before completely recrystalling. Larger quantities of the ethylene tetrapolysulfide give pliable materials which remain largely unchanged in properties for several weeks, following which hardening occurs on the recrystallization of sulfur.
"Mixtures of ethylene polysulfides with sulfur have been studied extensively to Tobolsky and coworkers [J. of Polymer Sci. A2, 1987 (1964)]. Both linear and crosslinked systems have been produced. Each produces extensive supercooling of sulfur. Systems containing as much as 40% supercooled liquid sulfur have remained free of crystallization for over three years."
In one of its embodiments, the present invention is also concerned with a method for preparing laminated conduit or pipe. Exemplary prior art patents in this area include U.S. Pat. Nos. 1,943,501, "Manufacture of Paper Tubes", for example shotgun shells; 3,055,278, "Reinforced Plastic Pipe"; 3,323,962, "Reinforced Resinous Tubular Laminates" for use in electrical insulating, etc.; and 3,767,500, "Method of Laminating Long Strips of Various Materials".